Transcript Roach: Introductory Clinical Pharmacology

Introduction to Clinical
Pharmacology
Chapter 25Adrenergic Blocking Drugs
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Adrenergic Blocking Drugs
• Drugs that reverse adrenergic drugs are adrenergic
blocking drugs also called sympatholytic drugs
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Alpha-Adrenergic Blocking Drugs:
Actions and Uses –ex-phentolamine
• Actions:
– Stimulation of alpha-adrenergic nerves
results in vasoconstriction
– Primary drugs used in this category causes
vasodilation
• Used for the treatment of:
– Hypertension during preoperative
preparation, hypertension caused by
pheochromocytoma, prevent or tx tissue
damage caused by dopamine extravasation
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Alpha-Adrenergic Blocking Drugs:
Adverse reactions, Contraindications and
Precautions
Adverse reactions:
– Weakness; orthostatic hypotension;
cardiac arrhythmias; hypotension;
tachycardia
• Contraindications and precautions:
– Contraindicated in patients who are
hypersensitive to drugs; patients with
coronary artery disease, MI
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Alpha-Adrenergic Blocking Drugs:
Contraindications and Precautions
• Contraindications and precautions (cont’d):
– Used cautiously during pregnancy and
lactation; after recent myocardial
infarction; patients with renal failure or
Raynaud’s disease
• When phentolamine is administered with
epinephrine there is decreased
vasoconstrictor and hypertensive action
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Beta-Adrenergic Blocking Drugs: Actions
• Actions:
– Decreased stimulation of sympathetic
nervous system on certain tissues
•B-adrenergic receptors are found
mainly in the heart, eyes (glaucoma)
– Decreased excitability of heart; decreased
cardiac workload and oxygen
consumption; provides membranestabilizing effects
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Beta-Adrenergic Blocking Drugs: Uses
and Adverse Reactions
• Used in treatment of:
– Hypertension; cardiac arrhythmias
migraine headaches; angina pectoris;
glaucoma, prevent reinfarction in pt’s
with recent MI (1-4 wks after MI)decreases HR and workload on heart
 Adverse Reactions:
 Cardiac reactions, gastrointestinal (GI)
reactions; bronchospasm; congestive
heart failure, vertigo
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Geriatric Alert
• Nurse should monitor the older adult closely for
confusion, heart failure, worsening of angina, shortness
of breath and peripheral vascular insufficiency (cold
extremities, parasthesia of the hands, weak peripheral
pulses)
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Beta-Adrenergic Blocking Drugs:
Contraindications and Precautions
• Contraindicated: Patients with allergy to beta
blockers; patients with sinus bradycardia;
second-or third-degree heart block; heart
failure; patient with asthma, emphysema, or
hypotension
• Drugs are used cautiously: Patients with
diabetes; thyrotoxicosis; peptic ulcer
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Beta-Adrenergic Blocking Drugs:
Interactions
Interactant drug
Effect of interaction
Antidepressants (MAOI,
SSRI)
Increased effect of beta
blocker, bradycardia
Nonsteroidal antiinflammatory drugs
(NSAIDs), salicylates
Decreased effect of the
beta blocker
Loop diuretics
Increased risk of
hypotension
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Alpha/Beta-Adrenergic Blocking Drugs:
Actions, Uses, and Adverse Reactions
• Actions:
– Blocks the stimulation of both the alphaand beta-adrenergic receptors, resulting
in peripheral vasodilation
• Uses:
– Carvedilol used for treatment of:
essential hypertension; in congestive
heart failure to reduce progression of
disease
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Alpha/Beta-Adrenergic Blocking Drugs:
Uses and Adverse Reactions
• Uses (cont’d):
– Labetalol used in treatment of:
Hypertension, alone or in combination
with another drug such as diuretic
• Adverse reactions :
– Fatigue; dizziness; hypotension;
drowsiness; insomnia; weakness;
diarrhea; dyspnea; chest pain;
bradycardia or skin rash
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Alpha/Beta-Adrenergic Blocking Drugs:
Contraindications and Precautions
• Contraindicated: Patients with
hypersensitivity to drugs; bronchial asthma;
decompensated heart failure; severe
bradycardia
• Used cautiously in patients with: Drugcontrolled congestive heart failure; chronic
bronchitis; impaired hepatic or cardiac
function; in those with diabetes; during
pregnancy and lactation
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Anti-Adrenergic Drugs: Actions and Uses
• Actions:
– Inhibits the release of norepinephrine from
certain adrenergic nerve endings in the
peripheral nervous system; affects specific
CNS centers, thereby decreasing some of the
activity of sympathetic nervous system
• Uses:
– Antiadrenergic drug used for treatment of:
Certain cardiac arrhythmias and hypertension
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Anti-Adrenergic Drugs: Adverse
Reactions
• Adverse reactions:
– Generalized reactions of drugs that work on
the CNS: Dry mouth; drowsiness; sedation;
anorexia; rash; malaise; weakness
– Hypotension; weakness; light-headedness;
bradycardia are adverse reactions associated
with administration of peripherally acting antiadrenergic drugs
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Anti-Adrenergic Drugs: Contraindications
and Precautions
• Contraindications and precautions:
– Contraindicated: In active hepatic
disease; antidepressant therapy using
MAOIs; patients with history of
hypersensitivity to these drugs
– Reserpine is contraindicated in patients
who have an active peptic ulcer or
ulcerative colitis and in patients who are
mentally depressed
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Anti-Adrenergic Drugs: Contraindications
and Precautions (cont’d)
• Used cautiously in patients with history of
liver disease; renal function impairment;
during pregnancy and lactation
• Reserpine is used cautiously in patients with
history of depression; in patients with renal
impairment or cardiovascular disease; during
pregnancy and lactation
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Anti-Adrenergic Drugs: Interactions
Interactant drug
Effect of interaction
Adrenergics, beta Increased risk of hypertension
blockers
Levodopa
Decreased effect of the
levodopa, hypotension
Anesthetic agents Increased effect of the anesthetic
Lithium
Increased risk of lithium toxicity
Haloperidol
(Haldol)
Increased risk of psychotic
behavior
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Nursing Process: Assessment
• Preadministration assessment:
– Nurse establishes an accurate database before any
adrenergic blocking drug is administered for the first
time
– Record onset, type, radiation, location, intensity,
duration of anginal pain when the drug is
administered for anginal pain
– Compare the current symptoms with the symptoms
before therapy
– Hypertension: blood pressure and pulse on both
arms
– cardiac arrhythmia: pulse rate, pulse rhythm, and
patient’s general appearance
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Nursing Process: Assessment
• Ongoing assessment:
– Observe the patient for appearance of
adverse reactions
– If propranolol is given for angina, ask the
patient about the relief of symptoms and
record responses patient’s chart
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Nursing Process: Planning
• Expected outcome:
– Optimal response to drug therapy:
– Meeting of patient needs related to
management of adverse reactions
– Understanding of and compliance with the
prescribed drug regimen
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Nursing Process: Implementation
• Promoting an optimal response to therapy:
– Administer drugs preventing release of
neurotransmitters
– Contact primary care provider immediately if angina
worsens or does not appear to be controlled by drug
– Monitors patient for decrease in blood pressure when
drug is administered for hypertension
– When a beta-adrenergic blocking ophthalmic
preparation, such as timolol, is administered to
patient with glaucoma, it is important to insist that
they have periodic follow-up examinations by an
ophthalmologist
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Nursing Process: Implementation
• Monitoring and managing patient needs:
– Impaired comfort:
•Report adverse reactions to primary
care provider; record the reactions on
patient’s chart; withhold next dose
when adverse reaction is
serious/potentially serious; relieve a
patient’s constipation by encouraging
increased fluid intake; maintain a daily
record of bowel elimination
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Nursing Alert
• When administering a sympatholytic drug such as
propranolol (Inderal), the nurse should take an
apical pulse rate and BP before administering the
drug.
– HR <60bpm
– IRREGULAR HR
– SBP<90 mmHg
– HOLD THE DRUG!!!!
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Nursing Process: Implementation
• Monitoring and managing patients needs (cont’d):
– Ineffective tissue perfusion:
cardiac/pheripheral:
• During therapy take patient’s blood pressure
before each dose is given
• The patients with a life-threatening
arrhythmia may receive an adrenergic
blocking drug, such as propranolol, by the
intravenous (IV) route; CARDIAC MONITORmonitor blood pressure, respiratory rate,
and rhythm
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Nursing Process: Implementation
• Educating the patient and family:
– Describe drug regimen and stress
importance of continued and
uninterrupted therapy when teaching
patient who is prescribed adrenergic
blocking drug
– Educating the patient with Hypertension,
Cardiac Arrhythmia, or Angina:
•Stress on importance of diet, weight
loss in therapy of hypertension
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Nursing Process: Implementation
• Educating the patient and family (cont’d):
• Advise hypertensive patient to lose weight
or eat a special diet, such as a low-salt diet
(MODIFIABLE RISK FACTORS)
– Educating the patient with glaucoma:
• The nurse demonstrates the technique of
eye drop instillation and explains the
prescribed treatment regimen to the patient
• Contact primary health care provider if eye
pain, excessive tearing, change in vision
occurs
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Nursing Process: Evaluation
• The therapeutic effect is achieved;
hypertension, cardiac arrhythmia, or
glaucoma is controlled
• Adverse reactions are identified, reported,
and managed successfully through
appropriate nursing interventions
• No evidence of injury related to orthostatic
(postural) hypotension is seen
• The patient and family demonstrate an
understanding of the drug regimen
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